The present disclosure relates to devices for dispensing highly viscous materials, such as viscous dental pastes. More particularly, it relates to handheld, manually operated devices for temporarily storing and selectively dispensing small quantities of viscous dental paste or other highly viscous materials.
Many clinical dental procedures involve the application of a dental composite material onto one or more teeth of the patient. Oftentimes, the dental material is highly viscous immediately prior to application (e.g., restoratives, core build up materials, etc.), and may further harden once applied. These dental materials are thus packaged and provided to the dentist or other end user in a paste-like (i.e., a thickened yet extrudable or pliable solid paste) form. The actual volume or amount of viscous dental paste required for a particular procedure varies from procedure-to-procedure, and most procedures entail sequentially applying small quantities of the dental paste to the same region. For example, an initial source volume or amount of the dental paste is made available to the dentist. The dentist retrieves a small quantity or portion of dental paste from this source volume (e.g., using a spatula or other instrument) and applies it to the patient's tooth (or other oral region). Later, another (and possibly additional) small portion is retrieved from the source volume and applied on top of the first application and/or to other regions in accordance with the procedure's recommended protocol.
In light of the above, viscous dental paste packaging desirably accounts for not only the high viscosity properties of the dental paste, but also normal usages in which the dentist must repeatedly retrieve and apply small amounts of the dental paste from a source volume. Because the application instrument(s) repeatedly contacts the dental paste source volume and the patient's mouth, any unused amount of the dental paste source volume cannot be used with a second patient due to possible cross-contamination concerns and is discarded. Moreover, many dental pastes are radiation-reactive and will solidify with sufficient exposure to ambient light. Once exposed to an excessive amount of ambient light, the dental paste will harden to a point that it is unusable and must be discarded. Thus, simply packaging a large volume of dental paste in a conventional lidded container is impractical. Conversely, because it is effectively impossible to know in advance the exact amount of dental paste needed for a particular procedure and the actual amount used can vary widely for different procedures, a “single use” packaging format is not preferred.
Further, many dental pastes are relatively expensive; the cost savings associated with a more bulk-like packaging format (as compared to single use) are desirable to dentists and their patients.
One well-received viscous dental paste packing format that addresses the above concerns is akin to a conventional syringe. As initially provided to the dentist, the syringe barrel (often formed of a light shielding material) maintains a volume of the dental paste sufficient to perform multiple procedures. The dispensing end of the barrel forms a relatively large opening, appropriate for manually-induced (i.e., manipulation of the syringe's plunger by the dentist's or other user's hand(s)) extrusion or dispensing of a highly viscous paste. Consistent with the above descriptions, while the packaged syringe is relatively small for convenient hand operation and thus the initial volume of contained viscous dental paste is also relatively small, most cosmetic and/or functional augmentation procedures require only a small portion of the packaged volume. As such, typically only a small quantity of the viscous dental paste is dispensed from the syringe in a progressive manner for each individual procedure. Although any unused amount of the dispensed dental paste is discarded, the volume still contained within the syringe is available for subsequent procedures. The syringe packaging format beneficially affords the dentist the ability to control the amount of dental paste actually dispensed for each procedure.
Because the dental paste is highly viscous, as it extrudes from the syringe barrel, the extruded strand will initially stay “connected” to the syringe (i.e., does not drip or immediately fall from the syringe barrel). While it may be possible to apply the dispensed quantity directly onto the patient's tooth as it is extruded from the syringe, most dentists highly prefer to employ a separate instrument, such as a spatula, to apply the material. With this in mind, the dentist will normally extrude and then “wipe” a small quantity of the viscous dental paste from the syringe onto a clean pad. The spatula or other instrument is utilized to retrieve small amounts of the dispensed quantity from the pad and then apply the retrieved dental paste to the patient's mouth. While viable, the amount of dispensed dental paste required by this technique is typically larger than actually needed for the procedure, leading to waste. Alternatively or in addition, the dentist may use the spatula to retrieve or “dig” a small amount from the extruded strand still “connected” to the syringe. This approach can lead to cross-contamination concerns, especially if the dentist inadvertently inserts the spatula into the relatively large barrel opening.
The highly viscous nature of many dental pastes in combination with normal procedures for dispensing small quantities of the material render current syringe-like packaging formats less than optimal. It is difficult to dispense only a small amount of the dental paste from the syringe, and existing syringe formats may encourage actions giving rise to cross-contamination concerns. Thus, a need exists for a viscous dental paste dispensing apparatus that maintains a bulk supply of dental paste, and facilitates safe and easy retrieval of smaller amounts by the dentist with minimal waste.